Magnetic wedge



Sept. 24, 1935. F. E. FISHER MAGNETIC WEDGE Filed Dec. 8, 1953Ihvehto1-= Frederick EF'isher;

His ttor'hey.

Patented Sept. 24, 1935 UNITED STATES MAGNETIC WEDGE Frederick E.Fisher, Scotia, N. Y., assignor to General Electric Company, acorporation of New York Application December 8, 1933, Serial No. 701,467

11 Claims.

My invention relates to magnetic wedges for closing the slots ofdynamo-electric machines or the like.

Wedges of magnetic material and particularly 5 wedges formed oflaminated magnetic material have substantial electrical advantages whenused to close or partially close the slots of dynamoelectric machines.This type of wedge has presented the mechanical difficulties ofcomplicated l assembly of the laminations and the further difficulty ofholding the wedges in place in the slots of the dynamo-electric machine.

An object of my invention is to provide a magnetic wedge in which thelaminations are formed '15 by folding a strip of magnetic material sothat folds of the material form transverse laminations.

Another object'of my invention is to provide a transversely laminatedmagnetic wedge having 20 a simple means for holding the laminations inassembled relation.

Further objects and advantages of my invention will become apparent asthe following description proceeds, and. the features of novelty 25which characterize my invention will be pointed out with particularityin the claims annexed to and forming a part of this specification.

For a better understanding of my invention, reference may be had to theaccompanying draw- 30 ing in which Fig. 1 is a perspective view ofwedges embodying my invention used to close the slots of adynamo-electric machine; Fig. 2 is a perspec tive view of one of themagnetic wedges shown in Fig. 1; Fig. 3 is a view of the strip ofmagnetic 35 material from which the wedge is formed; Fig. 4 is aperspective view of one of the side members of the magnetic wedge with afew of the folded laminations partially extended to show the manner ofmaking the side members; and Fig. 5 is a 40 perspective view of thebridge member which connects the side members of the wedge and retainsthe laminations in assembled relation.

I have shown my invention applied to a magnetic wedge of the type havingtwo side mem- 4 bers l which are shaped to fit in notches formed in theopposite sides of the slot of a dynamo-electric machine and which areconnected by a bridge member 3. Each of the side members is formed byfolding a strip of magnetic material 4 suc- 50 cessively in oppositedirections along the dotted lines indicated in Fig. 3, and pressing theadjacent folds together as indicated in the lower end of Fig. 4. Beforepressing the laminations together, the laminations may be coated with an55 insulating film to prevent the flow of eddy currents across thelaminations. The manner of folding is shown in the extended portion 5 ofFig.

4, and is such that one of the folds of the strip which constitutes atransverse lamination of the wedge isjoined to an adjacent fold oneither side 5 of said lamination at the top and bottom edges 4 of saidwedge respectively. The bridge member 3 which connects the side membersi of the magnetic wedge is preferably made of any suitable insulating ornon-magnetic material in the form 0 of an arch with transverse slots 6in the central portion of the arch. I a

The wedge is preferably assembled by placing the edges of a longitudinalbridge member 3 in slots 1 in the inner faces of the side members I andby crimping the lower edges 8 of the laminations against the bridgingmember to securely clamp the bridging member in the recess 1. Thedeformation of the edges 8 of the laminations causes the edges of thelamination to be clamped to the bridge member and grip the same, andsince the edges of the laminations are secured to the bridge member, thebridge member retains the laminations in assembled relation, providing aunitary wedge construction which can be driven into the slots. Thebridge member may be secured to the edges of the laminations by pressing the member into the recess, by molding the member in the recess, byplacing the member in the recess and expanding the member into tightengagement with the edges of the laminations, or by other suitablemethods. To further assist in retaining the laminations in assembledrelation, tabs 9 at the ends of member 3 are bent upwardly to engage theends of the side members i The wedge is placed in the dynamo-electricmachine by inserting or driving the Wedge in the slots [0 which arenotched to conform to the outer edges of the side members I. To assistin holding the wedge in place, the side members may be spread bydeforming the bridge member 3 along the central portion between membersI, after the wedge is in place. The slots 6 in the bridge member makedeformations of the bridge member easier and also lessen the eddycurrent loss if the bridge member is of metal. To further assist inholding the wedge in place, the wedge may be impregnated with aninsulating varnish or other compound.

Although I have shown a particular embodiment of my invention, I do notdesire to be limited to the construction described, and I intend in theappended claims to cover all modifications which do not depart from thespirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:-

1. A magnetic wedge having a plurality of laminations extendingtransversely of the length of said wedge, said laminations comprisingfolds of each member, and means for providing a unitary constructionincluding a member arranged in theredessineachmemberandsecuredtotheedges of said laminations for holdingsaid laminations in assembled relation and for connecting said sidemembers.

3. A magnetic wedge having side members. each member having a pluralityof laminations extending transversely thereof, said laminstionscomprising folds of a strip of magnetic material and having a recessextending longitudinally of each member, and a deformable bridgearranged in :the recesses in said side members and secured to the edgesof said laminations for joining said side members and retaining saidlaminations in assembled relation, said bridge being constructed so thatthe side members are spread apart when said bridge is deformed.

. 4. A magnetic wedge having side members, each member having apluralityof laminations extending transversely thereof, said laminationscomprising folds of a strip of m netic. material and having a recessextending longitudinally of eachmember, one of said laminations beingJoined to an adjacent lamination on either sideofsaidlaminationatthetopandbottomedges of said wedge respectively, andmeans for providing a unitary construction including amemberarranledintherecessineachmemberand secured to the edges of saidlaminations throughout the length of said member for holding saidlaminations in assembled relation and for connecting said side members.

I. A magnetic wedge comprising side members of magnetic material havinglaminations extending transversely thereof, and means for providing aunitary oonstructicnincluding a member extending between the inner facesof said side members for joining said side members and for retainingsaid laminations in assembled relation.

6. A magnetic wedge having a pluralityof laminations extendingtransversely of said wedge, said laminations having a recess extendinglons gitudinally along an edge of said wedge, and means for providing aunitary construction including a longitudinal member arranged in saidrecess and secured to the edges of said laminations for retaining saidlaminations in assembled 1o relation.

'1. A magnetic wedge comprising side members of magnetic material, eachside member having laminations extending transversely thereof and havinga longitudinal recess therein, and means 15 for providing a unitaryconstruction including a bridgemember arranged in said recesses andsecured to the edges of said laminations for joining said members andfor retaining said laminations in assembled relation. :9

8. The method of constructing a magnetic wedge which comprises the stepsof arranging a plurality of laminations extending transversely of saidwedge and having a recess extending longitudinally of said wedge,placing a longitudinal member in said recess, and securing said memberin said recess by deforming the sides of said recess to grip saidmember.

9. The methodof constructing a magnetic wedge which comprises the stepsof arranging a plurality of laminations extending transversely of saidwedge and having a recess extending longitudinally of said wedge,placing a longitudinal member in said recess, and deforming the sides ofsaid recess by crimping said laminstions against said member so that theedges of said laminations are secured to said member.

10. A magnetic wedge having a plurality of laminations extendingtransversely of said wedge, said laminations having a recess extendinglon- ,0 gitudinally along an edge of said wedge, and means for providinga unitary construction including a longitudinal member arranged in saidrecess and gripped by said laminations for retaining said laminations inassembled relation.

11. A magnetic wedge having a plurality of laminations extendingtransversely of said wedge,

said lamlnations having a recess extending longitudinaily along an edgeof said wedge, and means for providing a unitary construction includinga so longitudinal member arranged in said recess and gripped by theedges of said laminations for retaining said laminations in assembledrelation. FREDERICK E. FISHER.

